Embodiments of the present invention relate to mask triggering, and more particularly, to combinatorial mask triggering in the time or frequency domain on a test and measurement instrument.
Modern test and measurement instruments, such as high-speed digital oscilloscopes, include acquisition systems that capture measurement data pertaining to incoming electrical signals under test. Different kinds of criteria can be used to trigger an acquisition of data on the test and measurement instrument. For example, triggering can be based on a “mask region” defined within the drawing plane of a display device. Trigger logic can detect excursions of trace components represented by pixels drawn on the display within the mask region, and in response, cause a mask failure and/or trigger event to occur.
In a conventional frequency mask triggering system, a spectrum acquisition process is “free-running,” or in other words, as soon as the system is ready, acquisition data is acquired and processed to generate a spectrum. This spectrum is then rasterized into an image plane. As the individual spectrum traces or frequency components are rasterized, they are tested against the frequency mask. If the trace fails the mask criteria (e.g., an excursion through the mask region occurs), a trigger is generated, and digital data is acquired and stored in a memory.
In a conventional time domain triggering system, triggering can occur based on a variety of criteria. For example, acquired data can be tested against one or more “visual trigger zones” and if zone criteria are met, then the acquired waveform is processed further. If the zone criteria are not met, the waveform is discarded.
What is missing in conventional approaches is the element of time relative to special considerations. More specifically, while signals and relationships between components of signals can be expressed in terms of space and/or time, the conventional triggering methods lack the ability to build associations and trigger criteria around spatial aspects in combination with time-related aspects of the signal under test.
Moreover, while multiple mask regions or visual trigger zones are known, there remains a need for multiple region mask triggering and/or density triggering in both time and frequency domain acquisitions. Accordingly, a need remains for combinatorial mask triggering involving multiple trigger mask regions, along with trigger criteria involving logical, spatial and/or timing relationships between the mask regions, so that more sophisticated triggering modes can be supported. Embodiments of the invention address these and other limitations in the prior art.
The foregoing and other features and advantages of the inventive concepts will become more readily apparent from the following detailed description of the example embodiments, which proceeds with reference to the accompanying drawings.